for rays I would use a small pool sand filter with a multiport valve but you do need to back flush clean regularly before it cakes up. quick & easy but does waste water. you can either have a second higher pressure water pump for the back flush cycle or use a single variable flow pump that can be dialed up higher for flush then return to lower flow for filtration cycle.
If you require less maintenance then consider a self cleaning rotating drum if your budget allows. the combination ones with moving bed section would allow you to replace yours.
If you had more space, the best & simplest mechanical filter is a large settlement tank. kept outside. say 25,000 L rain tank . Just pull clean water from the top, have a bottom drain for yearly flush out of accumulated crap that drops out when water velocity slows. there are no moving parts or items to fail. your rays would appreciate the extra water in system.